Glycine zinc sulfate pentahydrate: redetermination at 10 K from time-of-flight neutron Laue diffraction

Abstract

We report a redetermination based on single-crystal neutron diffraction data and Raman spectra for glycine zinc sulfate penta­hydrate.

On Two Glycine Zinc Sulfate Phases with Exotic Cation Coordination Geometries

“…In addition the trigonal bipyramidal coordination sphere points to a thermodynamically metastable occurrence of the β‐polytype. The measured Zn–O distances within the ZnO 5 bipyramid, Zn–O(SO 4 ) = 2.02–2.13 Å and Zn–O(Gly) = 2.01 Å, are within the expected range for glycine zinc sulfates , …”

“…Structure solution and refinement of β‐Gly · ZnSO 4 was carried out using the program TOPAS 6.0 . Reflections in the powder pattern that could be neither assigned to α‐Gly · ZnSO 4 [12b] nor to Gly · ZnSO 4 · 2H 2 O were indexed by an iterative use of singular value decomposition (LSI) leading to a primitive monoclinic unit cell with lattice parameters given in Table and P 2 1 / c (no. 14) was determined as most probable space group from the observed systematic reflection extinctions.…”

“…The measured Zn-O distances within the ZnO 5 bipyramid, Zn-O(SO 4 ) = 2.02-2.13 Å and Zn-O(Gly) = 2.01 Å, are within the expected range for glycine zinc sulfates. [10,12] Due to the limits of the XRPD method no attempt was made to determine the hydrogen positions, but as the sample was obtained from aqueous solution, like all other known glycine zinc sulfates and as glycine occurs as a zwitterion in the known solid phases, [10,12a] it can be assumed that the amino acid is present as a zwitterion in the crystal structure of β-Gly•ZnSO 4 , as well. The coordination environment of the zwitterion is presented in Figure 3b.…”

“…The crystal structures of all phases are known. [10,12] In addition, the 1855 β-Gly-ZnSO 4 with space group P2 1 /c (no. 14) and a = 9.2577(1) Å, b = 5.1268(1) Å, c = 12.9926(1) Å, β = 90.267(1) and V = 616.65(1) Å 3 was solved ab initio.…”

Zinc‐containing compounds for personal care applications

“…). Conditions in which the complex was synthesized had to promote the existence of the ligand as a zwitterion + NH 3 –CH 2 –COO − , and therefore, it coordinated to Zn only by an oxygen atom . Likewise, in the case of another Zn complex [Zn(Gly) 2 I 2 ], the chelate was not formed and glycine adopted a monodentate coordination to the Zn 2+ (Fig.…”